The present invention relates to a speaker, more particularly to a loudspeaker with a diaphragm for producing sounds from input voice signal.
There are many loudspeakers with various forms of the diaphragm, including a cone type speaker having a conical diaphragm, a dome type speaker having the diaphragm formed in a convex or concave shape in a direction of sound emission, or the like. The cone type speaker is widely used as low, middle, and high-frequency sound speakers as well as a full-range speaker. The dome type speaker is widely spread, especially as a speaker having a small diameter and a relatively small amplitude for playing back a high frequency band.
The cone and dome type speakers also have various forms of the diaphragm. It is known that a curved cone diaphragm of the cone type speaker can have a wider playback frequency band than that of a flat cone diaphragm (see pages 32 to 33 of “New edition: Encyclopedia of Speaker & Enclosure” supervised by Tamon SAEKI, Seibundo Shinkosha Publishing Company, Apr. 10, 2001). The curved cone diaphragm has a convexly curved surface in the direction of the sound emission. The flat cone diaphragm has a flat surface. The dome type speaker has a diaphragm that has a central part thereof formed to be convex in the direction of the sound emission, and a circular part around the central part also formed to be convex in the direction of the sound emission. An upper end of a voice coil bobbin is mounted between the central convex part and the circular convex part around the central convex part (see Patent Application Laid-open No. 2003-153382).
In the above loudspeaker, the voice coil bobbin is mounted on the diaphragm, and a voice coil wound around the voice coil bobbin is disposed in a magnetic gap of a magnetic circuit. A voice signal is input to the voice coil so as to generate vibrations of the voice coil bobbin, which is then transmitted to the diaphragm to produce sounds. In general, a lead wire of the voice coil is fastened to the diaphragm, and is extended along the diaphragm to a terminal of a speaker frame or a connecting end of a tinsel wire connected to the terminal of the speaker frame in order to input the voice signal to the voice coil (see Patent Application Laid-open No. 2003-153382).
In the loudspeaker as mentioned above, the lead wire is fastened to the diaphragm, and is extended along the diaphragm to the terminal of the speaker frame or the connecting end of the tinsel wire connected to the terminal of the speaker frame. In particular, the following problem occurs in the loudspeaker having the diaphragm, a curved surface of which is formed to be convex in the direction of the sound emission as described above. The curved surface of the diaphragm is deformed to a large extent when the surface of the diaphragm is touched by hands and therefore the convexly curved surface of the diaphragm is crushed. Consequently, the lead wire is easily broken.
Furthermore, when the foregoing loudspeaker having the forward protruding diaphragm is displayed in an exhibition or a store, the diaphragm is often crushed by hands due to human psychology that a person wants to crush things that are protruded. Therefore, there occurs a problem that commercial value of the display is reduced after the diaphragm is damaged.